Disks are typically employed with disk drives for reading and writing data thereon. The disk or disks, in one embodiment, are removable while, in another embodiment are not intended to be removed by the user. In the case of removable disks, they are housed within a cartridge to facilitate handling and storage as well as to protect surfaces of the disks during installation and removal from the disk drive. As is known, the cartridge serves to seal the disk assembly from airborne contaminants and prevents unwanted contact with the disk surfaces.
In the most common example, the disk cartridge has at least one access opening through which a magnetic or optical read/write head can be received to record or read information on a surface of the disk. To prevent the collection of dust and/or fingerprints on the disk surface during periods in which the cartridge is not contained within a disk drive, a shutter or cover door, such as that shown in Nigam U.S. Pat. No. 4,503,474, is usually employed. As illustrated in the Nigam patent, the cover door is normally positioned across the access opening to seal the same, but can be retracted from the opening to permit access by a read/write head to one side of the disk.
In particular, the Nigam cartridge includes a camming arrangement which allows for automatic opening of the door as the cartridge is inserted into the disk drive unit. The Nigam camming arrangement, which is conceptually similar to door opening arrangements disclosed in Edwards U.S. Pat. No. 4,399,480 and Nigam, et al., U.S. Pat. No. 4,717,981, includes a cam arm and lever which are operatively connected to the door by way of a linking member. The camming arrangement is spring biased such that in a first position the door covers the access opening and in a second position the door is displaced with respect to the access opening such that optical or magnetic read/write operations can be performed with the disk. The cartridge includes an opening which is aligned with the cam arm such that when a cartridge is inserted within the disk drive the cam arm contacts a member disposed within the disk drive so that the camming arrangement urges the door into the second position.
While the door opening arrangement disclosed in Ohta U.S. Pat. No. 4,682,322 employs principles similar to that employed by the Nigam camming arrangement, the Ohta door(s) opening arrangement includes a rack and pinion assembly rather than a camming arrangement. More specifically, a transmission mechanism within the cartridge links a first rack and a second rack. The second rack is secured to a shutter, which is adapted to selectively cover an access opening overlying the disk, and the first rack is adapted to contact a projection as the disk is inserted into a disk drive. When the disk is not in use, the shutter, which is spring biased, covers the access opening. As the cartridge is inserted into the disk drive, the projection displaces the first rack, and consequently the second rack, such that the shutter is pulled away from the opening.
For a typical cartridge, the disk is mounted on a hub which, in turn, is mounted in an opening disposed within the housing of the cartridge so that the hub can engage with a spindle of the disk drive unit. There are various known arrangements for coupling the spindle with the hub. Typically, as illustrated in Takahashi, et al., U.S. Pat. No. 4,445,155, Nigam, U.S. Pat. No. 4,503,474, Nakamori, et al., U.S. Pat. No. 4,694,363, Maruyama, et al., U.S. Pat. No. 4,695,910 and Kato, U.S. Pat. No. 4,742,419, the hub includes a centering hole for receiving a spindle which includes a spindle supporting member and shaft. In Nakamori, et al., and Takahashi, et al., the hub is held to the spindle supporting member through the employment of one or more permanent magnetic pieces arranged about the spindle supporting member. On the other hand, in Maruyama, et al. and Kato the hub is secured within the disk drive by sandwiching it between the spindle supporting member and a collet.
Berthoux, et al., U.S. Pat. No. 4,078,246 discloses a coupling arrangement which may, for example, employ magnetic attraction, as with the Takahashi, et al. coupling arrangement. In particular, Berthoux, et al., discloses an arrangement which provides for air circulation within the cartridge while the disk is being rotated. That is, the Berthoux, et al., cartridge is characterized by opposing deformable walls which seal off the hub and disk when the cartridge is not in use, but allow for the formation of vents when the cassette is inserted into the disk drive. Moreover, the arrangement disclosed by Berthoux, et al. prohibits rotation of the disk when the cartridge is not being used in the disk drive.
The disk may be rotated through use of the spindle or a torque transferring member associated therewith. With the Nakamori, et al. and Nigam cartridges, for example, torque transfer is achieved through use of the spindle shaft alone. In particular, the spindle shaft is forcibly pressed into the centering hole which is slightly undersized relative to the spindle diameter. In contrast, torque transfer with the Maruyama, et al., Takahashi, et al. and Kato cartridges is achieved through employment of a drive shaft spaced from the spindle shaft. While each of the Maruyama, et al. and Takahashi et al. drive shafts are secured in a single drive pin insertion hole, the Kato drive shaft is positioned through use of an annular guide groove formed around the centering hole for the spindle and a rib. That is, the drive shaft is initially received by the guide groove and rides along the groove until it contacts, and is accordingly seated against, a wall formed by a rib.